Puix-open container



March 10, 1964 D. B. KAUFFELD PULL-OPEN CONTAINER Filed Dec.

Fig. 13

INVENTQR DON B. KAUFFELD ATTORNEYJ United States Patent G 3,124,295 PULL-OPEN CONTAINER Don B. Kaulfeld, Lexington, Ky., assignor to Foils Packaging Corporation, a corporation of Ohio Filed Dec. 1, 1961, Ser. No. 156,388 3 Claims. Cl. 229-43) This invention relates to an improved structure for paperboard containers, especially adapted for use in the packaging of frozen foods.

It is an important object of this invention to provide an improved leakproof container which can be easily and conveniently manufactured and sealed, and which is provided with a tear-open structure including a tab which when pulled outwardly opens one end of the container to the full cross-sectional area thereof so that the frozen food may be slid out of the container without catching on any peripheral restrictions around the opening.

It is another important object of the invention to provide an improved container structure which can be made of laminated paperboard material the core of which is highly absorbent to liquids, the structure of the container being such that all of the cut edges of the laminated blanks from which the container is made face outwardly of the sealing zones of the container seams and thus away from the contents thereof in order to prevent wetting of the exposed cut edges of the core thereby, known in the art as wicking.

Still another important object of the invention is to provide a container which can be made from paperboard blanks having their surfaces coated with a suitable plastic material which lends itself particularly well to heat-sealing techniques by which these plastic surfaces are welded together during forming and sealing of the container, as distinguished from glueing, although the present structure can also be glued if desired, or assembled by using any other suitable adhesive. Although the present container is suitable for packaging frozen foods, such as orange juice or soups, it is also suitable for use in the packaging of other products such as oils, jellies, syrups, acids, alkalies, detergents or bleaches, whether hot, cold or frozen.

Another major object of the invention is to provide a novel container having heat-sealed seam closures adapted especially for use in packaging frozen foods, such as frozen orange juice, wherein the sealing of the container after filling with a perishable food product is accomplished externally of the carton at positions which are remotely located with respect to the contents thereof so as to avoid melting-down of said contents during sealing.

Another very important object of the invention, associated with the previously mentioned object, is to reduce to a minimum the transfer of heat into the contents of the carton during sealing thereof by employing layers of metal foil laminated to at least one surface of each paperboard blank of which the container is made, and said metal foil rapidly conducting the heat away from the vicinity of heat application so that it may be quickly dissipated instead of remaining in the vicinity of the seal to penetrate the container and cause local melt-down.

Still another object of the invention is to provide a novel end structure which is especially strong so as to prevent distortion of the container or damage thereto as a result of dropping, but which end structure is perforated partly through in positions which are located outside of the sealing area, thereby to prevent leakage at the perforated area but at the same time to weaken the container in such a way that when a pull-tab is pulled outwardly the container will break open along the perforations and also break the plastic seal which is interposed between the perforate area and the contents of the container. This particular structure provides unexpectedly improved results based upon a novel combination of tearable mechanical structure which is however strong enough to hold the sealed panels in place, and heat-sealed seam structure in which the plastic provides water-tightness but at the same time provides a sealing zone which can be relatively easily pulled apart during opening. In working embodiments of the container shown in the present drawing, the structure was thoroughly watertight, and physically strong enough to prevent likelihood of physical damage, but at the same time could be torn open relatively easily by tearing of the paperboard laminate along the line of perforations and at the same time breaking the heat seal of one end panel with several side panels of the container. The heat-sealing thus cooperates especially well with the structure of the box and the location of the perforations therein to provide fully adequate sealing against leakage, while at the same time providing a reasonably easily opened structure. The container also includes an improved tear-open flap structure which is folded in such a way as to make the tear-open effort more efficient.

Other objects and advantages of the invention will become apparent during the following discussion of the drawings, wherein:

FIG. 1 is a plan view of a blank suitable for making the body portion of a container according to the present invention, embossed bend lines being shown as dashed lines, and perforations being shown as dotted lines;

FIG. 2 is a plan view of an end blank for a container according to the present invention, the dashed lines indicating embossed bend lines also in this figure;

FIG. 3 is an exploded perspective view of the body blank and end blanks;

FIG. 4 is an enlarged detail perspective view of one corner of a container during manufacture thereof, showing the end panel inserted in the body of the container;

FIG. 5 is a view similar to FIG. 4 but showing the container in a later stage of development in which the corners of the end flaps around the body panels of the container are being bent inwardly to overlie the flange flaps of the end blank;

FIG. 6 is a perspective view similar to FIG. 5, but showing the end flaps of the body blank fully folded over the flange flaps of the end panel;

FIG. 7 is a detail cross-section view taken along the line 7-7 of FIG. 6;

FIG. 8 is a perspective view on a smaller scale showing the end panel of a container fully sealed in the body thereof;

FIG. 9 is an enlarged cross-section view taken along line 99 of FIG. 8;

FIG. 10 is an enlarged cross-section view taken along line 10-1tl of FIG. 8;

FIG. 11 is a perspective view showing the container of FIG. 8 torn open to expose the contents thereof;

FIG. 12 is an enlarged cross-section view showing one form of laminated material from which the blanks and the container shown in the other figures may suitably be made; and

FIG. 13 is an enlarged cross-section view showing a modified form of the laminated material also suitable for use in making the blanks and container of the present invention.

Referring now to FIG. 1, the body blank comprises a plurality of body panels which form the side panels of the polygonal hollow body when set up as shown in FIG. 3. These panels comprise three complete panels 21, 31 and 41 and also a divided fourth panel 51 including portions 51:: and 51b joined respectively with the other panels and having a longitudinal seam tab 51c. These panels are all joined together by a plurality of embossed longitudinal bend lines 22, 32, 42, 52 and 62.

At least at one end of the hollow polygonal body formed by these body panels there is located a series of transverse crease lines 23, 33, 43, 53 and 63, and/or 24, 34, 44, 54 and 64, respectively dividing each end of the body into end flaps joined at these crease lines with the main body panels. These end flaps are respectively labeled 25, 35, 45, 55 and 65, and 26, 36, 46, 56 and 66. The embossed crease lines 24 and 44 are further each provided with a row of perforations 24 and 44 serving to weaken the paperboard for the purpose hereinafter explained. In addition, the end flaps are provided near each longitudinal bend line with diagonally disposedauxiliary crease lines such as 67, 68, 27, 28, etc. as shown in FIG. 1 and again in FIGS. 4, and 6.

Referring now to FIG. 2, this figure shows one of the end blanks of which two can be used to close the ends of the hollow polygonal body. The end blank shown in FIG. 2 is generally designated by the reference character 2, and further includes four flange flaps 3, 4, 5 and 6 all of which are mutually joined with the panel of the end blank by embossed crease lines labeled 7, S, 9 and 10. Note that the corners of the end blank are provided with further diagonal crease lines respectively labeled 3a, 4a, 5a and 6a, which permits each corner tab to be folded inwardly as shown in FIGS. 4, 5 and 7, and then flat against one of the adjacent flange flaps.

In addition, the end panel 2 includes an auxiliary flange flap 4b joined with the flange flap 4 at an embossed crease line 40, and having a pull-out tab 4d at its outer end. It is only necessary that the end panel at one of the two ends of the container have the auxiliary flange flap 4b and the pull-out tab 4d as will be hereinafter seen, the

other end panel being preferably symmetrical all the way around, omitting the pull-tab.

With reference to FIGS. 3 and 4 it will be seen that the end panel 2 has the flange flaps 3, 4, 5 and 6 bent outwardly at right angles and then inserted in the hollow polygonal body, preferably after the body has been seam-welded by lapping the panel 51a over the longitudinal seam tab 510 and the panel 511) and then seamwelding the structure in such a way that the raw cut edge along the outermost perimeter of the closure tab 51c is bent double as shown in FIG. and faces away from the contents of the container so as to prevent wicking at the cut edge of the tab Site. The end panel 2 is inserted to the depth shown in FIG. 4 such that the outer edges of its flange flaps are even with the crease lines 24, 34, 44, 54 and 64. Note that the little corner tabs in each corner of the end panel 2 fold flat against an adjacent flange flap, for instance the tab 4a folds flat against the flange flap 5. Then, the end flaps 25, 35, 45, 55 and 65 of the body are first folded inwardly at the corners about the diagonal crease lines 27 and 28, etc., as shown in FIG. 5, and subsequently the end flaps are folded about the transverse crease lines 24, 34, etc., so that these end flaps overlie and completely cover the flange flaps and the auxiliary flap 4b of the end panel 2, as shown in FIG. 6. In this final position, the end flaps 25 and 35 shown in FIG. 6 are again laid out flat at the crease lines 27 and 28' about which the corners were initially bent. In cross-section, this corner is as shown in FIG. 7.

Referring now to FIGS. 3, 8 and 9, it will be seen that in the case of the more complicated flange flap of the end panel 2, namely the flaps 4, 4b and 4d, the auxiliary flap 4b folds inwardly over the flange flap 4 and the pulltab 4d extends upwardly substantially parallel with the end panel 2, and this whole structure is held in place by the end flap 35, FIG. 8, which overlies it and which is welded to it. In the fully closed position the pull-tab 4b naturally lies flat against the surface of the end panel 2.

When it is desired to open this container, the pull-tab 4d is lifted outwardly to the position shown in FIG. 9

so that it can be firmly grasped by the fingers, and then is pulled outwardly to the extreme position shown in FIG. 9 so that it can be firmly grasped by the fingers, and then is pulled outwardly to the extreme position shown in .FIG. 11 to break the carton open. In opening the con 'tainer in this way, as can be seen by comparing FIGS. 9 and 11, the first thing that happens is that the pull-tab 4d pulls the flange flap 35 and the auxiliary flap 4b straight out to the position shown in FIG. 11 and breaks the welded seams between the end flap 35 and the auxiliary flap 4b. Also, the heat seal between the flange flap 4 and the inside of the body panel 31 is broken. Along this edge of the container substantially no tearing occurs. However, at the rows of perforations 24' and 44 as can be best seen in FIGS. 1, 3, 8 and 11, the attachment of the respective flanges 25 and 45 to their respective body panels 21 and 41 is weakened, thereby permitting the end flaps 25 and 45 to separate from the panels 21 and 41 when the container is pulled open to thereby facilitate opening of the container by tearing thereof along these two lines of perforations.

These perforations have been found desirable so as to permit the end flanges 25 and 45 to separate, because in the absence of these perforations 24' and 44', it is considerably more diflicult to tear open the carton in view of the fact that the end flanges 25 and 45 which are bent inwardly would present a great deal of resistance to such action. This type of resistance does not occur at the flap because of the fact that when the pull-tab 4:1 is pulled outwardly, as can best be seen in FIG. 9, it tends to lay the flap 35 out parallel with the panel 31 so that it does not have to be torn.

The crease lines 54 and 64 form a hinge which permits pivoting of the end panel 2 about this edge, FIG. 11.

Particular attention is drawn to the corner structure of the container which is very strong and which forms an excellent seal against possible liquid leakage, this structure being seen in cross-section in FIG. 3.

Referring now to FIG. 12, this figure shows on an enlarged scale a laminated material suitable for making the present blanks and containers. This laminate comprises a core of virgin kraft K coated on both sides with plastic, and the coating on at least one side of the laminate should be a heat-scalable material such as polyethylene P. For the sake of appearance, as well as for protection of the core K, the other surface of the container should also be coated with a plastic material such as polyethylene. However, alternatively this other coating can comprise some other plastic such as vinyl V, it merely being necessary that the other coating V will bond to the polyethylene P of the first coating when suflicient heat is applied thereto to fuse the polyethylene.

FIG. 13 is similar to FIG. 12 except that a metal foil F is interposed between one plastic coating and the inner core K for the sake of dissipating heat from the vicinity of an area being heat-sealed so as to prevent the heat in that area from reaching the contents of the container with such intensity that the contents may be melted down and damaged hereby. This foil F can be laminated to the kraft core K by any suitable means such as a waterbase latex, adhesive, or perhaps by still another layer of plastic material serving as an adhesive and located between the foil F and the core K. This adhesive, however, is not illustrated in FIG. 13, and the disclosure is not to be limited to a particular adhesive. It is only necessary that at least one of the external plastics be a weldable type which can be sealed at a temperature low enough that the kraft K will not be damaged by the heat applied. It is also contemplated that the laminate comprise cores other than a kraft core as referred to above.

Although the cross-section shape of the container illustrated in the drawing is rectangular, it is to be understood that this invention is not to be limited to this particular shape, but can be some other polygonal shape. The invention is not to be limited to the specific embodiments illus trated, since changes therein are possible within the scope of the following claims.

I claim:

1. An improved pull-open structure for a sheet material container of the type including side panels forming a hollow substantially polygonal body and having an end panel shaped to fit transversely across the end of the hollow body, and said end panel having flange flaps bent normal to the plane of the end panel to lie against the side panels of the body facing outwardly thereof, the improved pull-open structure comprising the following combination:

(a) an auxiliary flap joining along its inner edge the outer edge of one flange flap, and a pull-tab joining the auxiliary flap along the outer edge of the latter, the auxiliary flap being folded back to overlie the flange flap to which it is attached, and the pull-tab lying flat against the outer transverse surface of the end panel;

(b) and an end flap joining each body panel along a transverse crease line adjacent the outer edge of a flange flap, the end flaps being bent inwardly to overlie said flange flaps and said auxiliary flap, and said body having a row of perforations located along and coextensive with the transverse crease lines which are located adjacent to the crease line along the end flap which overlies said auxiliary flap, said perforations weakening the intersections between the related side panels and the end flaps thereby permitting the container to be torn open along the sides contiguous to the auxiliary flap when the pull-tab is pulled outwardly away from said transverse surface to pull the end panel away from the side panels.

2. In a container as set forth in claim 1, said sheet material having thermoplastic surfaces and said flaps and the body panels thereadjacent being heat-sealed together.

3. In a container as set forth in claim 1, said polygonal body comprising a sheet material blank comprising a plurality of mutually attached body panels bent to form a hollow body and joined along a longitudinal seam which is located substantially opposite to the panel of the container which lies along said auxiliary flap, and which seam comprises a tab disposed along one edge of the blank and bent back to lie flat on the outside of the blank and the other edge of the blank overlapping the tab and part of the blank thereadjacent and secured thereto, thereby protecting the cut edge of the tab from dampening by the contents of the container.

References Cited in the file of this patent UNITED STATES PATENTS 2,179,504 Hasbrook Nov. 14, 1939 2,333,330 Moore Nov. 2, 1943 2,665,616 Jungmayr Jan. 12, 1954 2,923,453 Eckman Feb. 2, 1960 

1. AN IMPROVED PULL-OPEN STRUCTURE FOR A SHEET MATERIAL CONTAINER OF THE TYPE INCLUDING SIDE PANELS FORMING A HOLLOW SUBSTANTIALLY POLYGONAL BODY AND HAVING AN END PANEL SHAPED TO FIT TRANSVERSELY ACROSS THE END OF THE HOLLOW BODY, AND SAID END PANEL HAVING FLANGE FLAPS BENT NORMAL TO THE PLANE OF THE END PANEL TO LIE AGAINST THE SIDE PANELS OF THE BODY FACING OUTWARDLY THEREOF, THE IMPROVED PULL-OPEN STRUCTURE COMPRISING THE FOLLOWING COMBINATION: (A) AN AUXILIARY FLAP JOINING ALONG ITS INNER EDGE THE OUTER EDGE OF ONE FLANGE FLAP, AND A PULL-TAB JOINING THE AUXILIARY FLAP ALONG THE OUTER EDGE OF THE LATTER, THE AUXILIARY FLAP BEING FOLDED BACK TO OVERLIE THE FLANGE FLAP TO WHICH IT IS ATTACHED, AND THE PULL-TAB LYING FLAT AGAINST THE OUTER TRANSVERSE SURFACE OF THE END PANEL; (B) AND AN END FLAP JOINING EACH BODY PANEL ALONG A TRANSVERSE CREASE LINE ADJACENT THE OUTER EDGE OF A FLANGE FLAP, THE END FLAPS BEING BENT INWARDLY TO OVERLIE SAID FLANGE FLAPS AND SAID AUXILIARY FLAP, AND SAID BODY HAVING A ROW OF PERFORATIONS LOCATED ALONG AND COEXTENSIVE WITH THE TRANSVERSE CREASE LINES WHICH ARE LOCATED ADJACENT TO THE CREASE LINE ALONG THE END FLAP WHICH OVERLIES SAID AUXILIARY FLAP, SAID PERFORATIONS WEAKENING THE INTERSECTIONS BETWEEN THE RELATED SIDE PANELS AND THE END FLAPS THEREBY PERMITTING THE CONTAINER TO BE TORN OPEN ALONG THE SIDES CONTIGUOUS TO THE AUXILIARY FLAP WHEN THE PULL-TAB IS PULLED OUTWARDLY AWAY FROM SAID TRANSVERSE SURFACE TO PULL THE END PANEL AWAY FROM THE SIDE PANELS. 